1,2,3,4-tetrachlorohexafluorobutane is a useful compound used as a raw material for synthesizing hexafluoro-1,3-butadiene which is a fine etching gas for semiconductors.
As a method of synthesizing a halogen compound having four carbon atoms, the following methods are known conventionally.
(1) Non-patent document 1 discloses that ICl is added to a raw material CClF═CF2 to prepare CClF2—CClFI, and then CClF2—CClF—CClF—CClF2 is synthesized in the presence of Hg by photo-reaction.
(2) Patent document 1 discloses that a raw material CClF═CF2 is reacted at 550° C. to prepare CF2═CF—CClF—CClF2, and then it is subjected to chlorination or bromination to prepare CClF2—CClF—CClF—CClF2 or CBrF2—CBrF—CClF—CClF2, respectively.
(3) Patent document 1, Patent document 2 and Non-Patent document 2 disclose that a raw material CF2═CF2 is subjected to iodine addition reaction or bromine addition reaction to prepare XCF2—CF2X (X═I or Br) and then it is subjected to telomerization reaction to synthesize XCF2—CF2—CF2—CF2X.
Patent document 1: Specification in U.S. Pat. No. 2,668,182
Patent document 2: Publication EP-B-0,270,956
Patent document 3: JP-A-62 (1987)-26240
Non-patent document 1: R. N. Haszeldine, J. Chem. Soc., 4423 (1952)
Non-patent document 2: J E. S. Elizabath, J. Org. Chem., 36 (1971)364